Crankshaft twister



June 16, 1936. A. T. HUNT I CRANKSHAFT TWISTER Filed April 6, 1931 6 Sheets-Sheet l June 16, 1936. A, T, HUNT CRANKSHAFT TWISTER Filed April 6, 1951 6 Sheets-Sheet 2 June 1%, 1936; T HUNT CRANKSHAFT TWISTER Filed April 6, 1951 6 Sheets-Sheet 3 June 16, 1936. A. T, HUNT CRANKSHAFT TWISTER Filed April 6, 1951 6 Sheets-Sheet 4 w mg A. T. HUNT CRANKSHAFT June l6, 1936.

TW-ISTER Filed April 6, 1931 6 Sheets-Sheet 5 6 Sheets-Sheet TWISTER A. T. HUNT CRANKSHAFT Filed April 6, 1951 june 16, 1936.

Patented June 16, 1936 CRANKSHAFT TWISTER Arthur T. Hunt, Fort Wayne, Ind., assignor to International Harvester Company, a corporation of New Jersey Application April 6, 1931, Serial No. 527,878

11 Claims.

In the manufacture of crank shafts for internal combustion engines, it is now common practice to forge a shaft blank having cranks in parallel or opposite position with the blank formed fiat. To complete the shaft, the blank is heated and locked into dies of a so-called crank shaft twisting machine. the function of. the machine being to twist the cranks, or certain of them, to the relative angular positions which they must assume in a finished crank shaft.

This invention relates to an improved crank shaft twisting machine, and the objects thereof are to provide a novel form of die-holding twisting elements; to provide improved means for rocking said. elements about fixed, aligned centers; to provide hold down means of novel construction for such elements to insure their proper turning movement about such aligned centers; to provide a simplified and improved driving mechanism for power actuating said rockable elements; and, lastly, generally to improve forging machines of this character.

Other important objects of the invention will appear to those skilled in this art as the disclosure is more fully made hereinafter.

The illustrative embodiment of the machine herein chosen for purposes of. the disclosure will be for twisting crank shafts of the six-cylinder, seven bearing variety as used in a six-cylinder internal combustion engine.

Briefly, the embodiment of the invention thus chosen involves a base carrying spaced brackets, certain of which serve to mount non-twisting clamps to lock certain portions of the crank shaft blank, while the remaining brackets carry arcuate roller tracks including rollers which serve to hold down half-circle rocker elements carrying clamps for holding the crank portions of the blank to be twisted to offset angular positions. These rocker elements all rock about non-physical, or imaginary points of turning, such centers all be ng aligned to produce an accurately aligned crank shaft. These movable rocker twisting elements are power actuated by means comprising pitmen driven from an eccentric mechanism. So much will sufiice for the present in portraying a general idea of the structure presently to be described in complete detail.

In the accompanying sheets of drawings,-

Figure l is a general end view of. the complete machine with a shaft blank locked therein ready parts as the twisting action takes place;

Figure 3 is a general plan view of the machine, as viewed in Figure 1;

Figure 4 is a longitudinal sectional view as seen along the line e-t shown in Figure 1, when viewed in the direction indicated by the arrows;

Figure 5 is a detail sectional view through a twisting element and a portion of the machine as viewed along the line 55 appearing in Figure 3, when looking in the indicated direction;

Figures 6 and '7 are, respectively, side and end elevational views of a twisting rocker element;

Figure 8 is a plan view of the power connections for driving the machine, including the starting and stopping control therefor;

Figures 9 and 10 are, respectively, plan and end views of the blank prior to twisting the same; and,

Figures 11 and 12 are, respectively, plan and end views of the completed, or twisted, crank shaft.

In mounting the machine, the floor of a forge shop is provided with a suitable bed I5, as shown in Figure 3. Formed as a part of the bed is the base 86 of the machine, which in practice will be raised to provide a horizontal table ll, as best appears in Figures 1 and 4. Said table ll carries in lengthwise alignment four vertically disposed, rectangularly shaped, wall-like brackets l8, i9, 28 and 2!, said brackets being spaced apart and disposed transversely in parallelism with each other. The brackets I3 and 2| constitute end brackets, while the brackets I9 and 20 constitute intermediately disposed brackets which may comprise, as shown, a unitary casting. See Figure 4.

Formed longitudinally through the brackets 3 l8, I9, 29 and 2! in alignment are bores that receive roller shafts 23 of short length in such a manner that each bracket journals one of said shafts. These shafts 23 in the end brackets l8 and 2! carry enlarged rollers 24 which fit in pockets 22 formed in the end brackets and project laterally a distance of the inner faces of said end brackets l8 and 2|. Thus, it will be seen that the shafts 23 of the end brackets have a roller 24 at one end only, whereas the shafts 23 carried in the intermediate brackets l9 and 20 have such rollers 24 at each end to fit in the pockets 22 on each face of said intermediate brackets l9 and 2D. The shafts 23 and rollers 24 so far described are on a longitudinal axis passed through the bottom-most of each of the pockets 22 in the respective brackets. From Figures 1 and 2 it will be noted that the two upper corners of each bracket carry additional shafts 23 and rollers 24 of. the

same kind, said rollers all being located on fixed axes in the respective roller carrying pockets 22. Thus, it is clear that there are three pockets 22 formed on each bracket face, said pockets carrying three spaced rollers 24 in the manner shown in Figures 1 and 2.

These rollers 24 serve as bearings and hold down means for the twisting rocker elements now to be described. Such rocker elements, are three in number, there being two at the ends and one in the middle, as viewed in Figure 4. A detail showing of the two end twisting rocker elements appears in Figures 6 and '7, where it will be seen that each comprises two vertical plates 25, each of a shape approximating the segment of a halfcircle. These two plates are separated by a spacer 26, the plates and spacers being suitably bolted together to form a unitary rocker element having a fiat upper surface along the diameter of the segment, as shown in Figure 6. Each outside face of the plates 25 is formed with a half-circle groove or track 2? in registration or alignment with the pockets 22 in the adjoining face of the brackets 58, i9, as the case may be. The rollers 24 fit into both track portions 21 and pockets 22, and so it is that the end twisting rocker elements are mounted on the brackets l8, I9 and 29, 2! for rocking movement in a circular path, and on the rollers 24 serving as bearings therefor, and further because the rollers are locked in the pockets 22 of the stationary brackets, 21. holddown action is exerted by the rollers on these rocker elements, so that in their movements they turn about an imaginary fixed axis of rotation.

The central or intermediate twisting rocker element is similar, but of a somewhat modified construction, the same comprising, as best appears from Figure 4, a unitary member having two spaced vertical plates 28 which also are approximately shaped like the segment of a halfcircle. These plates are connected by a diametric fiat top 29, and each outer face of said plates is formed with a roller track in, half-circle curvature of the kind heretofore described, said tracks receiving the two center rollers 24 to support said twisting element 28, 29 in its rocking movement, and also to hold said twisting member down, to insure its movement about a fixed, imaginary turning point as described in connection with the other twister rocker elements 25.

Normally, the fiat top sides of these rockable twister elements all lie flush with the top edges of the four brackets i3-2|, inclusive, as shown in Figure 1. All of these brackets are cross-braced and securely held on the base H by an angle beam 3!].

The two end twisting rocker elements 25, after the fashion shown in Figures Sand '7, each have secured to their top sides, a lower clamp element SI of a vise-fixture, which also includes a complementary, hinged, upper part 32 (see Figure 5). These two vise-fixtures are designed to clamp certain crank portions of the shaft blank. These fixtures include clamps 33 combined with conventional hand operated cam lever locks 34, whereby the blank may be securely held at the particular points mentioned. The intermediate rocker element 28 has similarly anchored to its top 29, a duplex vise-fixture having a lower jaw part 35 (see Figures 2 and 4) and a hingeduppe'r jaw part 36, the two jaw parts being likewise locked together to clamp two intermediate crank portionsof the blank, by means of a single, hand operated cam lever lock handle 31.

Carried on the brackets I9v and.20 are similar,

but non-twisting vise-fixtures 38 and 39, respectively, for locking two additional portions of the blank. These fixtures 38, 39 have cam lever locks 40 and 4| of the kind previously described.

Conventional air or steam operated piston cylinders are provided as additional means to hold these several vise-fixtures positively closed. Accordingly, the rocker element 25 at one end of the machine, as appears in Figure 1, carries a support 42 for pivotally mounting such a cylinder 43 having a push-pull rod 44 connected by a block 45. Likewise, the rocker element 25 at the other end of the machine is provided with a support 45, pivotally carrying an air or steam cylinder 4'? having a push-pull rod 43 connected by a block 49- to, the upper jaw 32 of the vise-fixture on the rocker 25 mentioned. See also Figure 5.

At the other side of the machine, the two intermediate brackets l9 and 20, respectively, carry supports 50, 5|. The support 53 pivotally mounts another cylinder 52 having a push-pull rod 53 connected by block 54 to the upper jaw of visefixture 38, while the support 5| pivotally mounts a cylinder 55 having a push-pullv rod 55 connected by a block 51 to the upper jaw of the visefixture 39.

To one side of the main part of the machine above described, the table ll carries two spaced, vertical brackets 58, as best shown in Figures 1 and 2. two vertically disposed A frames 59 spanned by a crosspiece 60, from which is pivotally hung another air or steam cylinder 5t having a pushpull rod 62 connected by a block 63 to the top jaw part of the duplexvise-fixture 36 carried by the intermediate twister rock member 29.

Two coaxially aligned shafts 54 are journaled one each in each bracket 58, said shafts being spaced apart at their inner ends where each carries a large gear 55, said two gears, as shown in Figure 3, being spaced apart and connected by an eccentrically disposed crank pin 56. Journaled on this pin is a pitman 61 having pivotal connection with the intermediate rockable twister element 29. The outer ends of each shaft 54 are provided with cranked ends 58 extending together in the same direction, which is opposite relative to the eccentric crank pin 66. Journaled on the cranks 68 are pitmen 69, one being pivotally connected to the rockable twister element 25 at one end of the machine, while the other pitman is pivotally connected to the rockable twister element 25 at the opposite end of the machine. The spacing apart of the two gears provided a space in which the intermediate pitman 51' plays, said pitman being appropriately connected to the rocker 29 between its spaced sides 28. As for the rockers 25, they too, it will be remembered, are constructed with spaced sides, so that, as shown in Figure 4, the pitmen 69 have room for play. The machine is so constructed that, as the two endpitmen 69 move in one direction, the intermediate pitman 61 moves in an opposite direction. The power connections for driving the gears 65 and cranks I58 will now be described.

Carried on any suitable extension 10 of the table I! (see Figures 1 and 8), is an electric motor H, the shaft of which is coupled to an in-and-out clutohgenerally shown at 12, having a shifter lever 13 connected with a horizontal shipper member 14 that is carried slidably in the eye '55 of two end supports"; connected to thebase extension 10,. as. shown. Continuing with the drive traingthe. power'passes the clutch-.12 to a suitable gear reducer-11. from which projects a shaft I8 These brackets 58 serve as supports for cylinders (see Figure 2) carried in journal brackets 19. This shaft 19 carries a wide pinion 80 in mesh with the two large gears 65 heretofore described. A brake 8| is included in the assembly, as shown in Figure 8.

Before describing the operation of the complete machine, it will be well to consider a type of crank shaft that may be twisted by the machine. The blank forging of the shaft has been illustrated in Figures 9 and 10, where it will be seen that the shaft, before twisting, is generally indicated at 82, the same being provided with six cranks, the two center ones of which, indicated at 83, and the cranks at the ends, indicated at 84, all extend in the same direction, while two intermediate cranks 85 are also provided to extend in the opposite direction. These cranks are all of uniform throw and, before twisting, appear flatly disposed, as shown in Figure 10. Preparatory to twisting the cranks, this blank is heated and, while still hot, the same is placed in the visefixtures of the machine in the manner best shown in Figures 3 and 4, it being understood that said vise-fixtures comprise upper and lower jaw parts, which have die depressions formed therein to conform to the shape of the cranks in the blank, in the manner well known to this art. The various cam lever locks 34, 31, 40 and 4| are then manually locked. Now, it can be seen that the two end cranks 84 are locked in the vise-fixtures carried by the two end twister rocker elements; the two center cranks 83 are similarly locked in the duplex vise-fixture carried on the center twister rocker element 29; and, lastly, the two intermediate cranks 85 are locked in the two intermediate vise-fixtures 38, 39, which are nonrockable, or fixed, as they are anchored securely and fast to the intermediate frame brackets l9 and 28. Appropriate valve control means, not herein d sclosed, will be operated to cause each of the pistons in the cylinders 43, 31, 52, 55 and iii to push on their respective rods positively to hold the several visefixtures closed, in a manner common in this art.

The purpose of twisting the cranks obviously is to offset the same relatively to each other to the final finished form which the shaft must assume when installed in a six cylinder internal combustion engine. Accordingly, the lever 13 is actuated by appropriate hand manipulation of the shipper bar M. Thus, the motor 1| drives the reduction gearing H, which in turn drives the wide pinion 80 and the two large gears 65 and their two shafts 64. As a result, the cranks 68 actuate the pitmen 69 toward the right, as viewed in Figures 3 and 5, to pull the two end rocker elements 25 upwardly through an arc of 120 degrees, causing the two cranks 84 of the shaft blank 82 to be twisted a like amount. At the .1 same time, the eccentric pin 66 drives the pitman 61 in the opposite direction, causing the central twister rocker element 29 to rock upwardly through an arc of 120 degrees and, as a result, the two central cranks S3 become twisted. This relative position of the parts just described is clearly shown in Figure 2. As for the two cranks 85, they are held stationary and thus they too become relatively oifset with respect to the other cranks 120 degrees. As all of the air or steam heretofore described are pivotally mounted, they are always effective to hold the vise-fixtures closed irrespective of the positions assumed by the rocker elements during the twisting operation.

The stroke of the pitmen 61 and 69 is such that the rocker elements 25, 28 can only move through their half-circle paths on the roller tracks heretofore described the desired distance necessary to twist the cranks in the shaft blank through the predetermined angular distance of 120 degrees. When the rocker elements have thus reached their maximum point of rocking movement, then the lever l3 will be actuated to stop the drive, whereupon the machine comes to a standstill. The brake 8| can be brought into play to overcome the inertia of the parts. Such control will be by hand, as far as the present disclosure goes, although the same can easily be made automatic, if desired. At this point in the operation, the shaft has been twisted and the machine is out of operation. Thereupon, the operator throws open the several cam lever locks 34, 3'5, 40 and 4|. Next, the machine is again set in operation by means of the lever 13 and simultaneously there with the valve control for the cylinders 43, Q1, 52, 55 and 6 I will be actuated in any appropriate way to reverse the pistons therein to cause the same to open the several vise-fixtures. As the machine has also now been set in operation, the pitmen 61 and 69 are reversed, whereupon the rocker elements are returned to their normal or starting positions with the vise-fixtures at this time fully opened and the twisted crank shaft released, to permit removal thereof from the machine. The machine is now ready to receive a new shaft blank and the operation is thus repeated for each shaft to be twisted.

The finished shaft is shown in Figures 11 and 12 and the same reference characters have been applied thereto as were used in Figures 9 and 10.

From the above disclosure, it must now be apparent that the rollers 24 provide an anti-friction track for the twister. rocking elements and further exert a hold-down action on such rocker elements, thereby insuring that these members always rock about an axis which is coextensive with the axis of the crank shaft in process. These rocker arms accordingly then have no physical, fixed axis, such as a pivot pin, but are instead held down and confined to rocking movement in half-circle paths about aligned, imaginary points or axes. This structure including the pitmen 67 and 69, plus the driving mechanism therefor achieves all of the desirable objects heretoforerecited for the invention.

It is the intention to cover all changes and modifications of the example herein disclosed, which do not, in material respects, constitute a departure from the invention as defined in the appended claims.

What is claimed is:

i. In a machine of the class described, a base, upright brackets carried thereon in spaced relaticnship, twisting elements rockingly carried between said upright brackets, rollers mounted in the brackets, tracks in the elements to receive the rollers, said rollers holding the elements down for movement about fixed axes, vise-fixtures carried by the twisting elements adapted to receive a crank shaft blank to be twisted, and means for rocking the twisting elements.

2. In a machine of the class described, a base, upright brackets carried thereon in spaced relationship, rollers carried in the brackets, halfcircle rocker elements provided with half-circle tracks to receive said rollers for rockingly mounting the elements on the brackets, vise-fixtures carried by the rocker elements, said fixtures adapted to clamp a crank shaft blank to be twisted, and means for rocking the twisting elements.

3. A crank shaft twister comprising, in cornbination, a base, a plurality of vertically disposed brackets carried by the base in spaced relationship, twister elements between the brackets, rollers between the brackets and twister elements, means for rocking said twister elements, said rollers being mounted on fixed axes in the brackets to carry the twister elements on the rackets and also to exert a hold-down action on the elements to confine them for turning movement about fixed aligned axes, and visefixtures carried by the twister elements adapted j to receive and clamp a crank shaft blank.

4. A crank shaft twister comprising, in combination, a base, a plurality of vertically disposed longitudinally aligned brackets carried by the base in spaced relationship, twister elements each a substantially in the shape of a half-circle arranged one each in the space between two adjoining brackets, half-circle tracks between the twister elements and brackets, rollers in the tracks to mount the twister elements on the brackets and to hold down said elements for movement about fixed, aligned axes, and a visefixture carried by each twister element adapted to receive a portion of a crank shaft blank to be twisted.

5. A crank shaft twister comprising, in combination, a base, a plurality of vertically disposed longitudinally aligned brackets carried by the base in spaced relationship, twister elements each substantially in the shape of a half-circle arranged one each in the space between two adjoining brackets, half-circle tracks formed in the twister elements, aligned shafts journaled in the brackets, said shafts carrying rollers arranged in said tracks, said rollers supporting the twister elements and exerting a; hold-down action thereon to insure their movement about fixed, aligned centers, means for rocking said twister elements, and vise-fixtures carried by said twister elements adapted to receive and clamp a crank shaft'blank to be twisted.

6. A crank shaft twister comprising, in combination, a base, four upright brackets arranged thereon in spaced relation and in longitudinal alignment, twister elements rockingly mounted between said brackets, comprising two end twister elements and an intermediate twister element, means for .maintaining said elements for movement about fixed aligned axes, fixtures on the twister elements for clamping a crank shaft blank to be twisted, a pitman for driving the intermediate twister element in one direction, pitrnen for simultaneously driving the end twister elements in the opposite direction, a pair of spaced gears having an eccentric pin therebetween for driving the intermediate pitman, means for rotating said pair of gears, and a pair of cranks driven from said gears, said end pitmen connected to be driven from said cranks, said cranks and eccentric pin being opposed whereby the intermediate pitman and end pitmen will be reciprocated in opposite directions.

7. A crank shaft twister comprising, in combination, a base, a pair of spaced brackets vertically disposed on said base, a rockable twister element carried between said brackets, said ele ment comprising a unit having two spaced sides, rollers between the said sides and adjoining surfaces of the brackets for carrying and holding said element for movement about a fixed axis, a pitman arranged between the sides of the element, means pivotally connecting the pitman to the element, means for reciprocating the pitman to rock the twister element, and a fixture secured tothe element adapted to clamp a portion of the shaft to be twisted.

8. A crank shaft twister comprising, in combination, a base, a plurality of upright brackets carried on the base in spaced relationship, rockable twister elements carried in the spaces between the brackets, fixtures on the rockable elements'to clamp portions of a crank shaft blank to be twisted, certain of said brackets carrying stationary fixtures to clamp other portions of the blank, means comprising tracks and rollers for carrying the rockable elements between the brackets and for holding said elements for movement about fixed, aligned axes, and means for rocking the rockable twister elements.

9. A crank shaft twister comprising, in combination, a base, a plurality of uprightv brackets carried on the base in spaced relationship, rockable twister elements carried in the spaces between the brackets, fixtures on the rockable elements to clamp portions of a crank shaft blank to be twisted,-certain of said brackets carrying stationary fixtures to clamp other portions of the blank, means comprising substantially half-circle tracks and rollers therein for carrying the rockabie elements between the brackets and for bolding said elements for movement about fixed, aligned axes, and reciprocatory means connected with the rocker elements for operating the same.

10. A machine for twisting a crank shaft for six cylinder engines, comprising, in combination, a base, four upright spaced brackets mounted on the base providingtwo end spaces and one intermediate space, end rockable twister elements in the end spaces including clamp fixtures for holding crank portions of the shaft tobe twisted, an intermediate rockable twister element in the intermediate space including a duplex clamp fixture for holding twocrank portions of the shaft to be twisted, non-twisting clamp fixtures carried on the two intermediate brackets for clamping two other crank portions of the shaft, means for holding the-rockable twister elements for turning movement about aligned axes, said means comprising rollers carried by the brackets and arranged in substantially half-circle tracks formed between adjacent faces of the brackets and the elements, pitmen pivotally connected to the end elements for rocking them together in one direction, and a pitman pivotally connected to the intermediate element for simultaneously rocking the same in the opposite direction.

11. A crank shaft forming machine comprising a stationary die and a movable die, the dies being recessed to receive a crank shaft portion and at least one of said dies'including a separable part to so clamp said portion, means on one die cooperating with means on the other for operatively supporting the movable die on the stationary die for movement thereon in an arcuate path.

ARTHUR T. HUNT. 

